Freight doggin isnt for everyone. It downright sucks at times, but I'll take better pay and a quick upgrade over low pay and better airplanes.
You have to ask yourself where do you want to be in 5 years? Still hanging around a regional or possibly at a major like Landlover said. Personally I'm taking the fast track to turbojet PIC. I'd rather pay my dues to the aviation gods quick and fast than slug it out at a regional.
Doggin is tough. We get dirty, tired, fly at all hours of the clock, fly crappy equipment, do runs into mexico at night with 15 year old basic GPS's and no terrain awareness equipment, hand fly everything except cruise flight, stay in shady hotels (sometimes), fly a 14 hour duty day and eat nothing but what FBO's have in their vending machines, switch from flying all night to flying during the day several times a week, learn the MEL list forwards and backwards, load 4,000lbs of freight by hand, some freight skates and a J-Bar, get screwed out of money by our hated company accountant, fuel planes ourselves (occasionally help the line guy if he's solo), have incompetent "so called" dispatchers, spend a lot of time away from our friends and family, work a lot harder than most pilots have to and we get stuck out on the road for up to 12 days in a row.
If you want a better QOL, fly nicer planes and can afford the absurdly low pay, go to a regional. But dont let people tell you that you wont get a better job later on in your career just because you flew 135. Thats a bunch of crap. Guys move on to bigger and better things from 135 all the time. Remember, its a lot about who you know, not what you know. I've met plenty of good contacts from 135 that will serve me well in about a year and a half when I get my 1000 turbojet PIC time.